A camera crew picked up Mr Prodi asking Mr Blair how long he had before he needs to decide on whether to hold an election.
At the EU summit in Stockholm, the prime minister was overheard talking to European Commission President Romano Prodi.
A camera crew picked up Mr Prodi asking Mr Blair how long he had before he needs to decide on whether to hold an election.
Mr Blair replied: "Ten days."
Noticing the presence of the camera, Mr Blair then returned to the official line that only the date of the local elections on 3 May has been fixed.
Totally focused
At a news conference later in Stockholm, Mr Blair pointed out he was totally focused on getting rid of foot-and-mouth.
He fended off questions about the timing of the election: "what I was saying in private was precisely what has been said in public.
"The main thing for me to do is to make sure that we have got the measures in place that allow us to control this disease," he said.
Responding to Mr Blair's overheard conversation, a spokesman for the prime minister in London said: "It's hardly surprising you get the odd leader asking about election timings at a summit like this.
"No decision has been taken about the date of the general election.
"On the local elections, if any decision is taken to postpone them, it would have to be taken in the near future, but there are no plans at this stage."
Michael Ancram
Conservative leader William Hague has already asked the government to prepare emergency legislation to postpone local elections in areas worst hit by the virus.
And the new watchdog set up to oversee elections is to ask for a guarantee that foot-and-mouth will not prevent "free and fair" voting if an election is called.
A spokeswoman for the Electoral Commission said: "We will be seeking assurances that voters in the affected areas will be able to receive election literature and will be in a position to vote without hindrance and by post if necessary."
Technically 5 April is the deadline for the dissolution of Parliament if an election is to be on 3 May.
Contempt
Tory chairman Michael Ancram seized on Mr Blair's comment.
"Mr Blair should be aware that if he calls an election, the contempt he has shown for the British people will be repaid in kind."
An opinion poll carried out in Mr Blair's Sedgefield constituency suggests a slim majority believe he should wait until after the crisis has subsided before calling an election.
The Northern Echo found that 50.7% of respondents believe the prime minister would be wrong to hold a 3 May poll.
35.7% believe he should go ahead, while 13.6% were undecided.